RCD's not tripping with TL transformers

[MorganPVI]

I believe i've been told 6ma can swamp a type AC RCD and can cause it not to trip.

 

[SolarCity]

Is this DC to grid leakage something which happens under running conditions or only under fault conditions?

 

[BruceB]

Normal running for Eversolar. SMA and Power One say theirs can't by design inject dc to grid. Have not looked up other manufacturers.

 

[SolarCity]

You learn something new every day - I always thought it was something that could happen under fault conditions only.

 

[grandfortune]

Darn, ill look more into it but it looks like ill have to fork out £200+ for type B rcd's.

 

[BruceB]

Or install in way that does not require an rcd. Normally relatively easy to do unless TT.

 

[grandfortune]

As a spark i find it almost impossible to install anything with a depth of 50mm, even in trunking i usually goes though some sort of wall or floor and the cable becomes less than 50mm somewhere along the line.

 

[BruceB]

A cable just going through a wall or floor from one side to another (say a wall from outside to trunking inside) does not bring in the 50mm rule. What I was suggesting was surface run swa, or solar cable or T&E in surface trunking. The only times I have 'had' to install rcds has been TT.

 

[SibertSolar]

Hmmm.....

TypeAC trip coil will saturate with any DC component, pulsed or pure
TypeA trip coil will saturate if the pulsed DC component is greater than 6mA but will saturate with any pure DC component
TypeB trip coil(s) will not saturate with either pulsed or pure DC component, regardless

Interesting thread. I shall monitor and try to offer assistance if required. For anyone needing pricing/stock of TypeA or TypeB RCDs then feel free to get in touch,

Andy

 

[SibertSolar]

Btw....if anyone's planning on visiting the SolarPowerUK show in B'ham in October then we'll have representatives from Doepke with us along with a demo unit to show how TypeA and TypeB RCDs operate.